I wasn't sure whether to put this topic in etiquette or religion, but I thought in religion people might know more about nuns, so...

One of the Sisters who taught at my boarding school had cancer and beat it! I was just invited to a party to celebrate. I was not asked to bring a gift, but this Sister was one of my favorites at school and I didn't even know she had been sick (nuns seem to be quite secretive about this stuff). Anyway I want to bring her something, but I'm not sure what you would get a nun, given that she's taken a vow of poverty and I know for a fact that these Sisters definitely live quite sparsely. Still, I want to show my appreciation for what a great teacher she was, and also how glad I am that she is all right.

I am an artist, and I usually give gifts of my art, like a painting or a sketch. However, the party is tomorrow and I don't think I'll have time to whip up anything by then. I have a lot of "spare" artwork on hand, but I had thought of painting her something religious, and I don't have anything like that. Anyway, just wondering what people think would be appropriate for her. I thought of just giving her a card saying that I am painting something for her and that it will be ready in a week's time, but is that tacky? Any comments or ideas would be appreciated.